An organic light emitting display device displays an image using organic light emitting diodes (OLEDs). With a soft OLED, flexible display devices such as a rollable display panel and a foldable display panel can be produced. However, during use of an OLED display panel, due to non-uniformity of parameters such as threshold voltages and mobility of driving thin film transistors (TFTs) in the OLED display panel, currents and brightness vary among different OLED display devices, resulting in spots. In addition, the drift of the threshold voltage of the TFT and the degradation of the OLED can also result in a difference in brightness of the pixels involved in a screen displayed on the OLED display panel, thereby resulting in a residual image.
In the conventional technology, the spots or the residual image are eliminated by performing image display compensation, which includes internal compensation and external compensation. According to the internal compensation, a sub-circuit is constructed among TFTs of pixels. This technology has advantages such as a low cost and easy implementation, but also has disadvantages such as a small compensation range, a poor compensation effect, and increased process difficulty. The external compensation includes an optical compensation method and an electrical compensation method, both of which utilize an external drive circuit or device to sense an optical characteristic or electrical characteristic of a pixel to perform compensation. The optical compensation method is advantageous in simple implementation, high flexibility and an improved resolution. The electrical compensation method can be performed in a real-time manner, and has a wide compensation range and an improved resolution. However, the optical compensation method can only be performed for a limited number of times, and involves a large amount of data, thus an additional storage space is required. The electrical compensation method is complex. Both methods result in a complex design of a control chip of the display panel.
A structure corresponding to an optical compensation method commonly used in the conventional technology is as shown in FIG. 1, a flowchart of the optical compensation method is as shown in FIG. 2, and description is made in conjunction with the structure shown in FIG. 1 and the flowchart shown in FIG. 2. In one embodiment, in the conventional technology, compensation is performed on a display panel after the display panel is produced and before the display panel leaves the factory. A compensation method includes the following steps S101 to S106.
In step S101, an OLED display panel 01 displays a test screen.
In step S102, original data on the display panel 01 is acquired by aligning a CCD 02 and focusing a lens.
In step S103, the CCD 02 transmits the acquired original data to a computer 03.
In step S104, the computer 03 processes the original data.
In step S105, the computer 03 generates compensation data based on the original data.
In step S106, the compensation data is written into a flash memory 04 of the display device.
Each time when the display panel is to display a new screen, and the control chip is powered on, the compensation data in the flash memory is loaded into a static memory inside the control chip, and the control chip invokes the compensation data in the static memory to perform compensation on the pixels on the display panel, and transmits compensated display data to the display panel for display.
Since the compensation data is written and is fixed before the display panel leaves the factory, the compensation data is no longer suitable for problems of the residual image or color shift caused by a change of a state of the display panel due to continuous use of the display panel after the display panel leaves the factory. Therefore, the compensation effect is poor and the compensation cannot be performed in real time.
In addition, since a large amount of compensation data which is proportional to the resolution is involved, an additional storage space is required, thereby resulting in increased space, time, and cost.
Therefore, an issue to be solved is to provide a method for performing compensation on a display panel image in a real-time manner with reduced amount of compensation data in subsequent use.